SERUM Software Engineering Risk: Understanding and Management COMM80: Risk Assessment of Systems Change Unit 15
Objectives of Session Coverage • To gain an overview of the SERUM method. • To understand the usage of SSM within it. • To understand the usage of Evolutionary Development within it. • To be able to compare it against other risk methods, for suitability of use and accessibility.
SERUM • Premise: “Change is inevitable for all commercial software systems” • For any application, there will be many potential changes. • Approach: tackle those changes that provide the best cost-benefit ratio. • But there is risk associated with any change. In particular technical risk and development risk,
SERUM Change Priority • Priority of change is expressed as a function of five variables. • risk exposure in the current system, • risk exposure in the proposed system, • risk exposure in the implementation of a change • cost of a defined change • benefit of a defined change
Method Composition • Soft Systems Methodology - Checkland • used in step 1 through to step 5
Method Composition • Evolutionary Development - Gilb • used in steps 6-9 and afterwards (outcomes from steps)
SSM in SERUM: Business analysis of the system • provides a set of recommendations for change (organisational and/or technological). • the recommendations define the gap between the current and the ideal model. • may identify major changes to an existing way of working. • Risk is associated with the disruption to the organisation.
Evolutionary development: plan the implementation of changes • Parts of a system are implemented and delivered in phases. • Each part is evaluated by the client • The feedback is used in implementing subsequent phases.
Evolutionary development • Development of measurable goals and attributes is crucial to this aspect. • Development relies on understanding the requirements and goals of the customer. • Gilb emphasises the need for • explicit goals, • measurable goals and • best case/worse case analyses.
Evolutionary development • Gilb emphasises the need for interaction between developers and • customers, • users, • budget controllers, • … • i.e. “stakeholders”
Evolutionary development • No mechanism exists for ensuring “correct/ appropriate” requirements. • But “goals and measurements” approach makes these more explicit and defined. • Development projects typically affected by vagueness: • Gilb’s approach requires developers to liaise with stakeholders to define goals and measurements.
SERUM and systems change • Users/decision makers involved in • “SSM” aspects • not in Evolutionary development aspect. • But • to control project when using evolutionary approach: ask for measurable goals from developers (whether internal or external). • Should use a two way mechanism.
SERUM and systems change • Is this more than an evolutionary development approach? • Yes: • provides framework • merger of SSM and evolutionary development strengthens Gilb’s approach. • Broader view of system than the software system.